Thy righteousness is an everlasting righteousness,.... Or, "is for ever" (z). The rectitude of his nature, his faithfulness in his promises, and his kindness and beneficence to his people; and particularly the righteousness of God revealed in the Gospel; the righteousness of his Son, which he approves and accepts of, and imputes to him that believes. This is a righteousness that will last for ever, will never be abolished; it will answer for them that have it in a time to come; it is of use throughout the whole of life, at death, in the day of judgment, and to all eternity; see Dan 9:24; and thy law is the truth; or "thy doctrine"; or "thy word", as the Arabic version. The Scriptures are called the Scriptures of truth, Dan 10:21 they come from the God of truth, and all that is contained in them is truth; the legal part of them is truth, and so is the Gospel; that is called the word of truth, and truth itself: it is concerning Christ, who is the truth; and it is directed into and made effectual by the Spirit of truth, and contains in it many excellent truths; and is therefore deservedly valued and esteemed by all good men; see Joh 17:17. (z) "in seculum", Pagninus, Montanus, Gejerus; "in aeternum", V. L. Michaelis.